From the prior art, peristaltic hose pumps are known, in which the rollers which occlude the inserted hose are resiliently mounted. The spring force in dependence on the compliance of the inserted hose determines the maximum afterpump pressure, at which an occlusion of the pump still exists.
Such peristaltic hose pump for example is known from DE 33 26 785 A1. Accordingly, in a pump rotor for peristaltically operating roller pumps, in particular for hose pumps in medical engineering, two roller carriers are in drive connection by means of two lever rods and two springs and are controlled such that the rollers rolling on a pump hose on the one hand are running on a rolling circle with constant diameter and on the other hand are able to independently adjust to pump hoses with different wall thicknesses or diameters.
In the case of a stenosis downstream of the pump, the pump pressure is limited to safe values and the hose bursting or a succeeding filter, such as a dialysis filter, being damaged is prevented. In addition, a patient whose blood, for example in connection with a dialysis treatment, is delivered for the dialysis by means of such peristaltic hose pump in an extracorporeal blood circuit, can be prevented from being put in danger at a later time.
The required spring constant with which the rollers are pressed against the inserted hose is dependent on the chosen type of treatment, the inserted hose and the succeeding filter and thus is variable.
In the peristaltic hose pumps known from the prior art, changed requirements concerning the spring force by means of which the rollers are pressed against the hose inserted into the peristaltic hose pump can only be realized by a replacement of the spring, which often is equivalent to a replacement of the rotor. However, this is comparatively expensive. In addition, the gradations of the spring force generally are not arbitrarily small, so that it is not possible to actually adjust to any desired force, but possibly required adaptation of the occlusion force.
In addition, during the assembly and disassembly of the pump with the hose, manual force must be applied in addition, in order to compress the rollers to such an extent that the hose can also be inserted into the pump bed.